The invention relates to a knitting machine needle for a stitch-forming machine, in particular for a knitting machine, for the production of flat textile material.
In order to produce knit material with a pattern, for example, it is possible to use knitting machines with latch-type needles and/or slider needles. Consistent with the pattern, individual stitches are transferred from one knitting machine needle to another knitting machine needle. To achieve this, the needles, which are referred to as transfer needles or rehanging needles, comprise special stitch transfer elements.
Document DE 199 05 668 A1 has disclosed such rehanging needles are configured as latch-type needles. Such a latch-type needle opens and closes the interior hook space by means of a tongue that is mounted so as to be pivotable about a tongue slit. It has, on one of its flat sides, a stitch transfer element in the form of a rehanging spring. In order to allow an adjacent needle or oppositely arranged needle to able to take up a stitch it moves along the needle base body over the rehanging spring and, in so doing, said stitch is expanded. In order to ensure this operation, the needle base body has a rounded pocket into which immerses the tip of the rehanging spring, so that the stitch can slide onto the rehanging spring without being impaired. A lateral bias of the rehanging spring imparted by the stitch that is sliding on or by the (knitted) material that is being drawn off causes the tip of the rehanging spring to move back and forth in the rounded pocket in longitudinal direction of the needle. In doing so, there is the risk that the rehanging spring will be permanently bent, thus potentially causing the tip to no longer immerse completely into the pocket of the needle base body. A tip of the rehanging spring located outside the pocket impairs the stitch transfer operation. The projecting tip may impair the stitch or half stitch as it is sliding on. The half stitch may be speared by the tip.
Document DE 42 31 015 C2 has disclosed knitting machine needles that are rehanging needles configured as slider needles, which have a slider extending in longitudinal direction through its shaft in order to open and close a hook supported by said shaft. A rehanging spring is laterally attached to the slider needle, whereby said spring defines an intermediate space with the needle shaft, through which space the hook and the shaft of another knitting machine needle may pass. Only one end of the rehanging spring is attached to the needle body. The other end of the rehanging spring is tapered and sinks into a needle pocket provided in the needle base body. Consequently, it is possible for a half stitch to slide—starting at the hook's interior space, as the knitting machine needle is being driven out—over said needle's shaft and the rehanging spring, whereby the half stitch is expanded. As a result of this enlargement of the stitch loop of the half stitch, in conjunction with the tensile force due to the goods being drawn off, a load is applied to the rehanging spring, causing said spring to brace itself with its spring tip against the bottom of the needle pocket. The force that acts on the rehanging spring causes the spring tip to move in the direction of the needle hook, whereby the size of the intermediate space existing between the rehanging spring and the needle base body is minimally reduced. The load that is applied in the region of the tip of the rehanging spring as a result of the impacting force of the half stitch and the goods being drawn off may be large enough to cause the rehanging spring to be severely bent, so that the tip is no longer completely received by the spring pocket. This may have the result that the tip of the rehanging spring will spear the half stitch when it is supposed to slide over the needle base body. Consequently, the half stitch will no longer slide onto the rehanging spring. If the tip of the rehanging spring is lifted far enough for the half stitch to slide through under the tip of the rehanging spring, a rehanging of a stitch is no longer possible. Then, the reliable rehanging of the knitted goods is no longer ensured.
Additional rehanging needles are known from documents DE-OS 28 47 972 A1 and DE-OS 30 18 699. All the rehanging needles disclosed therein have a cutout in the base body, whereby the tip of the rehanging spring immerses into said cutout. In all cases, the bottom of the cutouts is flat, whereby a few individual cutouts have a rounded end. When a load is applied to the rehanging spring of the disclosed rehanging needles in the direction of the flat side of the needle base body, there is the risk that the shape of the rehanging spring will permanently change and that, consequently, the rehanging operation is hindered. This risk is particularly great in the case of a rehanging needle in accordance with DE-OS 30 18 699 because this rehanging spring is a so-called draw-in spring. When the needle is retracted into the needle channel, the rehanging spring is pressed flat against the needle body by the channel strip. This represents a particularly high stress on the rehanging spring.
Considering this, it is the object of the invention to develop rehanging needles with which the rehanging process is ensured over the longest possible period of time. It is the objective of the invention to improve the useful life of such rehanging needles.